1. Field of the Invention
The present invention relates to a Light Emitting Diode (LED) package incorporating a diffuser to facilitate color mixing and to a manufacturing method of the same. More particularly, the invention relates to an LED package in which a diffuser is applied to an encapsulant disposed in an upper part of an LED chip to achieve color mixing, enabling uniform emission without distortion of light from the LED chip in a wide radiating angle, thereby facilitating color mixing while reducing a thickness and enhancing a degree of freedom of a lens part, and to a manufacturing method of the same.
2. Description of the Related Art
In general, various sizes of LED packages are used for backlight units of mobile phones or Personal Digital Assistants (PDAs).
Such conventional LED packages are increasingly reduced in its thickness as the backlight units are becoming slimmer.
For such backlight units, the LED packages are popular as light sources therefor, and thus various structures or shapes of LED package are currently examined and developed.
The LED packages used for LCD Televisions or monitors are structurally categorized into an edge lighting type, a top emitter, and a side emitter. The most important factor among these LED packages is to achieve good color mixing to make a white light source.
Such an example of a conventional LED package is illustrated in FIG. 1.
The conventional LED package 200, disclosed in U.S. Patent No. 2005-0057144, includes a substrate 205 with electrode patterns 207a and 207b formed thereon, and an LED chip 210 mounted on the electrode pattern 207b and electrically connected to the electrode patterns 207a and 207b by wires 211.
The conventional LED package 200 has a reflecting frame 212 disposed on the substrate 205 for housing the LED chip 210, and a reflecting layer 214 formed on an inner side of the reflecting frame 212. The reflecting layer 214 serving as a reflecting surface is made of Al and/or Ag having high reflectivity deposited or painted thereon.
In addition, a wavelength-converting material part 220 is formed in an inner space of the reflecting frame 212 where the LED chip 210 is mounted. The wavelength-converting material part 220 comprises transparent resin containing a phosphor 222a and a diffuser 222b, and encapsulates the LED chip 210.
In the above-described LED package 200, when emission takes place from the LED chip 210 and light is emitted, the light is directed to the wavelength-converting material part 220 by the reflecting layer 214. The light then collides with the phosphor 222a contained in the wavelength-converting part 220 to excite the phosphor 222a, and is scattered by a plurality of diffusers 222b contained in the wavelength-converting material part 220. As a result, light having a longer wavelength than the light that was incident onto the phosphor 222a exits the package due to the interaction between the phosphor 222a and the diffuser 222b. 
Although the conventional technology is useful for elongating the wavelength of light emitted from the LED chip 210 and emitting white light, it does not necessarily allow uniform light emission. The conventional technology allows color mixing to generate white light, but emits white light only forward without a variety in radiating angles. Further, as it realizes white light using the phosphor 222a, it has mediocre color reproducibility.
Another conventional LED package 250 is illustrated in FIG. 2.
As disclosed in Japanese Patent Application Publication No. 2001-60724, the LED package 250 includes an LED chip 260 positioned in a lamp housing 255 having a hollow part, electrodes 262a and 262b drawn out from the LED chip 260, and an encapsulant 270 filled in the lamp housing 255 for fixing the LED chip 260 and the electrodes 262a and 262b. 
In such a conventional LED package 250, the lamp housing 255 having a hollow part is disposed such that its emitting surface is positioned in a lower part. Then, the encapsulant 270 composed of transparent thermosetting resin with glass beads 272 having a high refractive ratio mixed therein at a suitable ratio is injected into the hollow part of the lamp housing 255 from the back of the LED chip 260.
Then, after the glass beads 272 precipitate in the encapsulant 270 made of transparent thermosetting resin, the encapsulant 270 is heated and cured to complete the LED package 250.
In such a conventional LED package 250, the glass beads 272 in the encapsulant 270 of transparent thermosetting resin function as a diffuser and scatter light to some degree. However, the light is directed only forward in a not-so-wide radiating angle due to the hollow part of the lamp housing 255, and it is difficult to reduce the thickness of the LED package 250 due to the structural characteristics of the electrodes 262a and 262b and the lamp housing 255.
In addition, the conventional LED package 250 is complicated to manufacture, thus not suitable for mass production.
FIG. 3 illustrates yet another conventional LED package 300. The conventional LED package 300 includes a base substrate 305 with electrodes 310a and 310b formed thereon, an LED chip 312 mounted on and connected to the electrodes 310a and 310b, and a molded frame 315 having a groove, thus being fixed around the LED chip 312.
Then, a molding member 317 containing a diffuser 317a is filled in the groove of the molded frame 315. This conventional LED package 300 achieves high luminance and contrast ratio using the diffuser 317a contained in the molding member 317 made of transparent resin, thereby enabling a high contrast display in a large angle of visibility in high precision.
However, the conventional LED package 300 also emits light only forward from the molded frame 315, and does not achieve excellent light emission.
When applied to the backlight units to produce white light using red, green, and blue lights, each of the above described LED packages 200, 250 and 300 is required in a plural number to uniformly illuminate a large area and mix colors, increasing the number of components.
Therefore, the conventional LED packages 200, 250 and 300 result in increased manufacturing costs of the LCD products due to the increased number of components.